The following invention relates to a printhead module assembly for a printer.
More particularly, though not exclusively, the invention relates to a printhead module assembly for an A4 pagewidth drop on demand printer capable of printing up to 1600 dpi photographic quality at up to 160 pages per minute.
The overall design of a printer in which the printhead module assembly can be utilized revolves around the use of replaceable printhead modules in an array approximately 8xc2xd inches (21 cm) long. An advantage of such a system is the ability to easily remove and replace any defective modules in a printhead array. This would eliminate having to scrap an entire printhead if only one chip is defective.
A printhead module in such a printer can be comprised of a xe2x80x9cMemjetxe2x80x9d chip, being a chip having mounted thereon a vast number of thermo-actuators in micro-mechanics and micro-electromechanical systems (MEMS). Such actuators might be those as disclosed in U.S. Pat. No. 6,044,646 to the present applicant, however, might be other MEMS print chips.
In a typical embodiment, eleven xe2x80x9cMemjetxe2x80x9d tiles can butt together in a metal channel to form a complete 8xc2xd inch printhead assembly.
The printhead, being the environment within which the printhead module assemblies of the present invention are to be situated, might typically have six ink chambers and be capable of printing four color process (CMYK) as well as infra-red ink and fixative. An air pump would supply filtered air through a seventh chamber to the printhead, which could be used to keep foreign particles away from its ink nozzles.
Each printhead module receives ink via an elastomeric extrusion that transfers the ink. Typically, the printhead assembly is suitable for printing A4 paper without the need for scanning movement of the printhead across the paper width.
The printheads themselves are modular, so printhead arrays can be configured to form printheads of arbitrary width.
Additionally, a second printhead assembly can be mounted on the opposite side of a paper feed path to enable double-sided high speed printing.
It is an object of the present invention to provide an improved printhead module assembly.
It is another object of the invention to provide a printhead assembly having improved modules therein.
The present invention provides a printhead module for a printhead assembly incorporating a plurality of said modules positioned substantially across a pagewidth in a drop on demand ink jet printer, comprising:
an upper micro-molding locating a print chip having a plurality of ink jet nozzles, the upper micro-molding having ink channels delivering ink to said print chip,
a lower micro-molding having inlets through which ink is received from a source of ink, and
a mid-package film adhered between said upper and lower micro-moldings and having holes through which ink passes from the lower micro-molding to the upper micro-molding.
Preferably the mid-package film is made of an inert polymer.
Preferably the holes of the mid-package film are laser ablated.
Preferably the mid-package film has an adhesive layer on opposed faces thereof, providing adhesion between the upper micro-molding, the mid-package film and the lower micro-molding.
Preferably the upper micro-molding has an alignment pin passing through an aperture in the mid-package film and received within a recess in the lower micro-molding, the pin serving to align the upper micro-molding, the mid-package film and the lower micro-molding when they are bonded together.
Preferably the inlets of the lower micro-molding are formed on an underside thereof.
Preferably six said inlets are provided for individual inks.
Preferably the lower micro-molding also includes an air inlet.
Preferably the air inlet includes a slot extending across the lower micro-molding.
Preferably the upper micro-molding includes exit holes corresponding to inlets on a backing layer of the print chip.
Preferably the backing layer is made of silicon.
Preferably the printhead module further comprises an elastomeric pad on an edge of the lower micro-molding.
Preferably the upper and lower micro-moldings are made of Liquid Crystal Polymer (LCP).
Preferably an upper surface of the upper micro-molding has a series of alternating air inlets and outlets cooperative with a capping device to redirect a flow of air through the upper micro-molding.
Preferably each printhead module has an elastomeric pad on an edge of its lower micro-molding, the elastomeric pads bearing against an inner surface of the channel to positively locate the printhead modules within the channel.
As used herein, the term xe2x80x9cinkxe2x80x9d is intended to mean any fluid which flows through the printhead to be delivered to print media. The fluid may be one of many different colored inks, infra-red ink, a fixative or the like.